Studies On Biological Active Pyrazole Derivatives

Pyrazole derivatives, one of the focuses in the research and development of agrochemicals, has been found to show widespread biological activities. Many of them have been used pesticide, fungicide, herbicide and medicine. In this paper, we designed and synthesized three series of new compounds according to the principle of combination of bioactive substructure and bioisoteric relationship. The structures of the target compounds (I_3a-I_3m, II_3a- II_3q, III_3a- III_3j) have been confirmed by ¹H NMR, EI-MS, IR, elementary analysis and the X-ray crystallography for I_3c, I₃₁, III_3f and the intermediate III-2.The preliminary bioassay of the new compounds mentioned were measured. The results showed that the compounds of I_3a-I_3m and III_3aæ¡°II_3j possessed excellent fungicidal activities. In particular, compounds of I_3aæ¡°_3j showed about 100% inhibitory rate to Botrytis cinereapers at the dosage of 50mg/L. They can be further investigated as lead compounds.